There is heightened awareness of fire prevention in homes and businesses in the United States. This awareness has led to the development of standards and legislation directed to reducing the risk of fires, particularly with respect to bedding and upholstered furniture. Conventional fire prevention techniques for bedding and upholstered furniture involve the topical application of flame retardant chemicals directly to an outer decorative layer of upholstery material.
However, recently passed legislation may render conventional fire protection techniques for bedding (particularly mattresses) inadequate. For example, the cigarette burn test for measuring flame resistance (developed by the Upholstered Furniture Action Council) has been deemed inadequate by the state of California and by the U.S. Consumer Product Safety Commission. In addition, new regulations being promulgated in some states and at the federal level prohibit the sale or manufacture of mattresses that do not pass these new flammability tests.
For example, California Technical Bulletin 603 of the State of California Department of Consumer Affairs (hereinafter “TB-603”), which is incorporated herein by reference in its entirety, exposes the top and side panels of a mattress to an open gas flame to simulate the effects of burning bedclothes. TB-603 is extremely aggressive relative to conventional cigarette burn test and many industry analysts are skeptical that conventional upholstered furniture and bedding products (e.g., mattresses, etc.) will be able to pass TB-603. Aggressive federal standards for flammability of mattresses are currently being proposed by the U.S. Consumer Product so Safety Commission and are described in the Federal Register at 16 CFR 1633 (hereinafter “16 CFR 1633”).
In addition, material that can prevent the propagation of flame into the core cushioning material of furniture, and institutional bedding is desired. California Technical Bulletin 117 of the State of California Department of Consumer Affairs (hereinafter “TB-117”), which is incorporated herein by reference in its entirety, provides testing for upholstered furniture, and California Technical Bulletin 129 of the State of California Department of Consumer Affairs (hereinafter “TB-129”), which is incorporated herein by reference in its entirety, provides testing for institutional bedding.
In some cases, even though an upholstery fabric or ticking is constructed of inherently flame resistant material, it may be permeable such that heat and hot gases may be transmitted through the fabric causing internal materials to ignite. Furthermore, conventional methods of assembling mattresses and upholstered furniture may produce seams and joints that cannot withstand these new flammability tests without splitting open and subjecting flammable interior materials to flame. Also, pores formed in bedding fabrics as a result of sewing, seaming, quilting, and/or the attachment of labels, handles, decorations, vents, etc., may be penetrated by flames and hot gases which may result in the combustion of interior materials.
The top and side panels of a mattress are typically composed of layers of material. Typically the outer layer is a decorative ticking fabric that is a high quality knit or woven textile. The next layer is typically a cushioning layer, such as foam, batting, or other lofty, soft material. The cushioning layer provides a plump, soft, feel and texture to the panel. The next layer is typically a backing fabric that supports the cushioning material and provides strength and dimensional stability to the panel. The backing layer may be optional if the second layer is strong enough and stable enough to support the structure. Additionally, some mattress or upholstery panels are flat and do not have significant ‘plumping’ or cushioning, but must still provide the insulation and flame resistance required by the new standards. The backing layer is conventionally a polyester or polypropylene nonwoven fabric, a knit, or a woven fabric. The layers of a mattress panel are typically assembled via stitch quilting. Stitching, however, may create unacceptable compression and perforation of a structure, and may negatively affect flame and heat resistance of the mattress. Conventionally, a flame and heat blocking component is added to the panel when the panel is designed to resist heat, fire, or ignition.
Filler cloth panels may or may not be multi-layered when providing flame resistant protection. If multi-layered, the outer layer may or may not be decorative, but usually is comprised of a stitchbonded, needlepunched, hydroentangled, or spunbonded fabric treated or designed to provide a desired coefficient of friction in addition to the required flame resistance.
To prevent the ignition of the core of a mattress, or other upholstered article, a variety of flame resistant materials have been utilized in the construction of top and side panels for mattresses. For example, fabrics made from graphite, carbon, para-aramid, or other flame and heat resistant fibers have been used. Batting composed of flame resistant fibers or fibers that char, such as silica modified rayon (or Visil), modacrylic, FR rayon, FR polyester, melamine, or other suitable fibers may be produced such that at high basis weights can provide flame resistance and insulation. Foams may be chemically treated with flame retardant or impregnated with graphite. Fabrics may also be treated with flame retardant and/or intumescent chemical compositions or impregnated with intumescent chemicals to provide flame blocking and insulative properties.
In addition, the use of thermoplastic backing fabrics in mattress construction, such as a polypropylene spunbonded nonwoven, may result in the melting and shrinking away of the backing fabric when exposed to heat and/or flame. This shrinking or opening force can draw cracks and holes into the mattress structure when the mattress is exposed to high heat. Additionally, molten thermoplastic can soak into the cushioning material and increase flammability of the mattress. Unless an appropriate fire resistant bottom panel is utilized, fire can enter from beneath a mattress or foundation, or upholstered furniture, and propagate across the inside surface of the flame resistant panel.
U.S. Pat. No. 6,823,548 to Murphy describes a flame and heat resistant material wrapped around the core of a mattress. The flame resistant material is separate from the aesthetic ticking of the mattress exterior and requires additional processing which may add to manufacturing costs. Moreover, the Murphy flame resistant material risks the loss of protection if misalignment occurs between the material and a mattress core, and the protection cannot be varied for the different challenges seen in the various parts of the mattress or foundation.
Multi-layer panels for conventional mattresses are constructed by acquiring separate layers of material and joining them together. For example, see U.S. Pat. No. 6,954,956 to Diaz and U.S. Pat. No. 4,504,991 to Klanczik. In order to provide resistance to high temperatures of a flame, and to provide strength to the panel structure after burning, conventional multi-layer mattress panels require the use of high temperature fibers that are inherently flame resistant and that do not melt or decompose at temperatures around 500° F. (260° C.)). Examples of such fibers include aramid fibers, carbon fibers, glass fibers, polybenzimidazole fibers and Visil® brand fibers, which can be expensive.
In addition, multi-layer panels for conventional mattresses may be treated with intumescent coatings. Unfortunately, these coatings can be thick and heavy and can impart an undesirable stiffness, loss of loft and cushioning to the mattress panels. In addition, intumescent coatings can add considerably to the expense of conventional mattress panels.